This invention relates to a position indicating valve, and particularly to a new and improved means for sensing and indicating valve position.
Heretofore, various means have been employed to sense and/or indicate the position of relatively movable valve members which otherwise are hidden from view or isolated so that the condition of the valve cannot be readily determined. Such sensing or position indication of valve condition is considerably important when it is desirous to sense and indicate valve position at a location quite remote from the valve itself.
For instance, it may be required to sense and indicate valve position, at a central monitoring station, of a number of valves remotely and widely distributed throughout a system. Remote position sensing thus is required to indicate full opening and closing of valves when it is impractical to otherwise know if the valves are stuck open, shut or inbetween. Additionally, a number of valves may be assembled into a module, and it is desirous to sense and/or indicate the position of the various valves by use of printed circuitry, for instance.
Previous attempts have been made to satisfy the abovedescribed needs by providing reed or proximity switches, eddy current sensors, or the like, for providing position indicating means for valves, particularly solenoid valves. For instance, U.S. Pat. No. 4,004,258 to Kurt Arnold, dated Jan. 18, 1977, and entitled "Position Indicating Pulse Latching Solenoid", shows a valve which is operated by a solenoid plunger. A reed switch senses the momentary flux generated by the excited solenoid winding at a leakage gap near one of the valve stops and determines whether the flux imparted to the plunger by the permanent magnets has shifted with the plunger toward or away from the leakage gap to indicate plunger position. This and other position indicating means require separate switching parts which may require adjustments at various times to accommodate variances in current, valve stroke, or the like. Such devices also are somewhat ineffective when very little pull force is available within the valve. Such devices also require space requirements for properly positioning the separate switches and their respective switch contacts.
The present invention is directed to satisfying the above needs and solving the above problems by utilizing valve seat and seal members as switch contacts in a sensing circuit, thereby achieving precise and exact indication of valve position. Remote indication is readily available because the switch contacts defined by the valve seat and seal can be electrically coupled through a wide variety of circuit means to appropriate remote indicators at indication stations. With the valve seat and seal members acting as direct contacts, it is evident that extra sensing apparatus or devices are not required and there is no need to provide extra space therefore, particularly in very small valve constructions. Furthermore, absolutely no adjustments are required of the indicating means of the present invention because the valve seat and seal members themselves define the electrical contacts within the sensing circuit and, of course, they will at all times correspond to the relative contact positioning.
A principal object, therefore, of the present invention is to provide a new and improved position indicating valve.
Another object of the invention is to utilize valve seat and seal members as direct switch contacts within the valve position indicating circuit system.
In the exemplary embodiment of the invention, a position indicating valve is shown and described in which a housing has a valve port, and a valve member is mounted on the housing for movement toward and away from the valve port. An electrically conductive valve seat is disposed about the valve port, and an electrically conductive valve seal is disposed on the valve member for movement therewith into and out of contact with the conductive valve seat. Circuit means is coupled to each of the valve seat and valve seal, whereby the circuit means is closed when the seat and seal are in contact with each other.
The valve constructions shown herein are embodied in solenoid valves which include reciprocal plungers. A valve seal(s) of conductive elastomer material is embedded in one or both ends of the plunger. The conductive seals engage inlet and exhaust conduits which themselves are fabricated of conductive material. The conduits define ports and extend through the valve housing to the exterior thereof for coupling to appropriate lead means of the sensing circuit.
In order to complete a circuit to the valve seals of the plunger, the plunger itself is fabricated of conductive material, a portion of the valve housing is conductive, and a conductive spring means is sandwiched between the plunger and the conductive housing portion, with electrical lead means of the sensing circuit coupled to the conductive housing portion.
Thus, it can be seen that a new and improved construction is provided in fulfillment of the above objects and advantages of the invention. Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.